The Large Red-belted Clearwing (Synanthedon culiciformis) is a fascinating, day-flying moth that mimics a wasp and is experiencing a surge in recorded sightings in Scotland thanks to pheromone technology. Here are some interesting facts about the species in Scotland:
Surprising Scottish Surge: Once considered very rare in Scotland, recent use of synthetic pheromone lures has revealed this moth to be more widespread than previously thought, with records ranging from the Borders to the Great Glen and Moray.
"Knapdale" Discovery: In 2024, the species was recorded in Knapdale, near Mid-Argyll, following its discovery in that area in 2023.
New Location Records: New sites for the species have recently been found at Glen Finglas in the Trossachs and at Tummel Bridge in Perthshire, showing its active expansion in Scottish recording efforts.
Western Expansion: Although historically more common in the east, a 2021 record from Mull suggests the species is expanding its known range in the west of Scotland.
Birch Stump Specialist: In Scotland, the caterpillars have a distinct preference for feeding inside the recently cut stumps of birch trees.
Distinctive Appearance: It is identified by a wide, bright red band across its abdomen and a distinct scattering of red scales at the base of its wings, which sets it apart from other British clearwings.
Early Riser: It is one of the earliest clearwing species to fly, typically found in May and June.
Pheromone Attraction: Males are highly attracted to pheromone lures (specifically the CUL lure) during sunny afternoon periods, often between 13:00 and 19:15.